From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59501) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z7Lsf-0005b3-27 for qemu-devel@nongnu.org; Tue, 23 Jun 2015 06:56:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z7LsY-0001qY-Se for qemu-devel@nongnu.org; Tue, 23 Jun 2015 06:56:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58003) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z7LsY-0001qA-Ko for qemu-devel@nongnu.org; Tue, 23 Jun 2015 06:56:34 -0400 Date: Tue, 23 Jun 2015 12:56:31 +0200 From: "Michael S. Tsirkin" Message-ID: <20150623125126-mutt-send-email-mst@redhat.com> References: <1434650744-6585-1-git-send-email-marcel@redhat.com> <20150623115705-mutt-send-email-mst@redhat.com> <5589338E.80304@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5589338E.80304@redhat.com> Subject: Re: [Qemu-devel] [PATCH] net/virtio: fix multi-queue negotiation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marcel Apfelbaum Cc: famz@redhat.com, qemu-devel@nongnu.org, n.nikolaev@virtualopensystems.com On Tue, Jun 23, 2015 at 01:23:10PM +0300, Marcel Apfelbaum wrote: > On 06/23/2015 12:57 PM, Michael S. Tsirkin wrote: > >On Thu, Jun 18, 2015 at 09:05:44PM +0300, Marcel Apfelbaum wrote: > >>Clear host multi-queue related features if the peer > >>doesn't support it. > >> > >>Signed-off-by: Marcel Apfelbaum > >>--- > >>Notes: > >> This fixes a guest CPU soft lock, however the virtio-net > >> device will not work correctly. It seems that is > >> peer's "fault", not knowing how to handle the situation. > >> However, I submit this patch since it corrects the negotiation > >> and saves us from a guest crash (!). > >> > >> Any ideas from the virtio/multi-queue developers on how to debug > >> this further are welcomed. > >> > >> hw/net/virtio-net.c | 13 ++++++++++++- > >> 1 file changed, 12 insertions(+), 1 deletion(-) > >> > >>diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > >>index 9281aa1..63e59e8 100644 > >>--- a/hw/net/virtio-net.c > >>+++ b/hw/net/virtio-net.c > >>@@ -367,6 +367,11 @@ static int peer_has_ufo(VirtIONet *n) > >> return n->has_ufo; > >> } > >> > >>+static int peer_has_multiqueue(VirtIONet *n) > >>+{ > >>+ return n->multiqueue; > >>+} > >>+ > >> static void virtio_net_set_mrg_rx_bufs(VirtIONet *n, int mergeable_rx_bufs, > >> int version_1) > >> { > >>@@ -469,6 +474,13 @@ static uint64_t virtio_net_get_features(VirtIODevice *vdev, uint64_t features) > >> virtio_clear_feature(&features, VIRTIO_NET_F_HOST_UFO); > >> } > >> > >>+ if (!peer_has_multiqueue(n)) { > >>+ virtio_clear_feature(&features, VIRTIO_NET_F_MQ); > >>+ virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_ANNOUNCE); > >>+ virtio_clear_feature(&features, VIRTIO_NET_F_CTRL_VQ); > >>+ virtio_clear_feature(&features, VIRTIO_NET_F_CTRL_RX); > >>+ } > >>+ > >> if (!get_vhost_net(nc->peer)) { > >> virtio_add_feature(&features, VIRTIO_F_VERSION_1); > >> return features; > > > >_MQ makes sense but what about the rest? Why clear them? > Guest's virtio driver doesn't like if MQ is off and any of the other flags remains ON. > It has a specific check for each of them and fails the loading if not all are off. > > Thanks, > Marcel I think you are mistaken. if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) && (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX, "VIRTIO_NET_F_CTRL_VQ") || VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN, "VIRTIO_NET_F_CTRL_VQ") || VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE, "VIRTIO_NET_F_CTRL_VQ") || VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") || VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR, "VIRTIO_NET_F_CTRL_VQ"))) { return false; } return true; So if CTRL VQ is not set, you can not have MQ or any of the others. > > > >>@@ -1314,7 +1326,6 @@ static void virtio_net_tx_bh(void *opaque) > >> static void virtio_net_set_multiqueue(VirtIONet *n, int multiqueue) > >> { > >> n->multiqueue = multiqueue; > >>- > >> virtio_net_set_queues(n); > >> } > >> > >>-- > >>2.1.0